Paper chromatography or ion-exchange paper chromatography is a procedure which enables the separation of ions and polar molecules on the basis of the charge properties of these molecules. It can be used for several sorts of charged molecules such as large proteins, little nucleotides and amino acids. The solution to be injected is normally known as a sample and the independently separated components are identified as analyses. It is often utilized in protein purification, water analysis and for quality control purposes. Ion exchange paper chromatography keeps analyze molecules using coulombic ionic interactions. The stationary phase surface exhibits ionic functional groups that interact with analyze ions of opposite charge. This category of paper chromatography could be further subdivided into cation exchange paper chromatography and anion exchange paper chromatography. The ionic compound comprising the cationic species and the anionic species may be retained by the stationary phase.

Cation exchange paper chromatography keeps positively charged cations because the stationary phase exhibits a negatively charged functional class. Anion exchange paper chromatography keeps anions displaying a positively charged functional class. Note that the ion power of cations or anions in the mobile phase may be adjusted to alter the balance position and, hence, the retention period. An ion chromatogram can be used to reveal that the chromatogram obtained with an ion exchange column. A normal paper chromatography technique involves the introduction of a sample either manually or using an auto sampler, into a sample loop of known quantity. A buffered aqueous solution called the mobile phase carries the sample out of the loop into a column that comprises some kind of stationary phase material. This is normally a resin or gel matrix which includes agarose or cellulose beads with covalently bonded charged functional groups. The target analyses anions or cations are kept on the stationary phase but may be eluted by increasing the concentration of a similarly charged species.

So as to control an paper chromatography system, Paper Chromatography data system is usually required. Some of the paper chromatography data systems are also used to control gas paper chromatography and HPLC systems. Paper chromatography separates proteins according to their net charge. This depends upon the composition of the mobile phase. By way of instance, if a protein has a net positive charge at pH 7, then it will bind to a column of negatively-charged beads, but a negatively charged protein will not. Changing the pH so the net charge on the protein is negative will make it also be eluted. Accomplishing elution by changing the ionic strength of the mobile phase is a more subtle effect. It works because ions from the cell phase will interact with the trapped ions in preference to those on the stationary phase. This protects the static phase from the protein and vice versa. This permits the protein to elute. A preparative-scale ion exchange column is used for protein purification.